README.EXT_SKEL

(NOTE: you may also want to take a look at the pear package
PECL_Gen, a PHP-only alternative for this script that
supports way more extension writing tasks and is
supposed to replace ext_skel completely in the long run ...)
WHAT IT IS
It's a tool for automatically creating the basic framework for a PHP module
and writing C code handling arguments passed to your functions from a simple
configuration file. See an example at the end of this file.
HOW TO USE IT
Very simple. First, change to the ext/ directory of the PHP 4 sources. If
you just need the basic framework and will be writing all the code in your
functions yourself, you can now do
./ext_skel --extname=module_name
and everything you need is placed in directory module_name.
[ Note that GNU awk is likely required for this script to work. Debian
systems seem to default to using mawk, so you may need to change the
#! line in skeleton/create_stubs and the cat $proto | awk line in
ext_skel to use gawk explicitly. ]
If you don't need to test the existence of any external header files,
libraries or functions in them, the module is already almost ready to be
compiled in PHP. Just remove 3 comments in your_module_name/config.m4,
change back up to PHP sources top directory, and do
./buildconf; ./configure --enable-module_name; make
But if you already have planned the overall scheme of your module, what
functions it will contain, their return types and the arguments they take
(a very good idea) and don't want to bother yourself with creating function
definitions and handling arguments passed yourself, it's time to create a
function definitions file, which you will give as an argument to ext_skel
with option
--proto=filename.
FORMAT OF FUNCTION DEFINITIONS FILE
All the definitions must be on one line. In it's simplest form, it's just
the function name, e.g.
my_function
but then you'll be left with an almost empty function body without any
argument handling.
Arguments are given in parenthesis after the function name, and are of
the form 'argument_type argument_name'. Arguments are separated from each
other with a comma and optional space. Argument_type can be one of int,
bool, double, float, string, array, object or mixed.
An optional argument is separated from the previous by an optional space,
then '[' and of course comma and optional space, like all the other
arguments. You should close a row of optional arguments with same amount of
']'s as there where '['s. Currently, it does not harm if you forget to do it
or there is a wrong amount of ']'s, but this may change in the future.
An additional short description may be added after the parameters.
If present it will be filled into the 'proto' header comments in the stubs
code and the <refpurpose> tag in the XML documentation.
An example:
my_function(int arg1, int arg2 [, int arg3 [, int arg4]]) this is my 1st
Arguments arg3 and arg4 are optional.
If possible, the function definition should also contain it's return type
in front of the definition. It's not actually used for any C code generating
purposes but PHP in-source documentation instead, and as such, very useful.
It can be any of int, double, string, bool, array, object, resource, mixed
or void.
The file must contain nothing else but function definitions, no comments or
empty lines.
OTHER OPTIONS
--no-help
By default, ext_skel creates both comments in the source code and a test
function to help first time module writers to get started and testing
configuring and compiling their module. This option turns off all such things
which may just annoy experienced PHP module coders. Especially useful with
--stubs=file
which will leave out also all module specific stuff and write just function
stubs with function value declarations and passed argument handling, and
function entries and definitions at the end of the file, for copying and
pasting into an already existing module.
--assign-params
--string-lens
By default, function proto 'void foo(string bar)' creates the following:
...
zval **bar;
... (zend_get_parameters_ex() called in the middle...)
convert_to_string_ex(bar);
Specifying both of these options changes the generated code to:
...
zval **bar_arg;
int bar_len;
char *bar = NULL;
... (zend_get_parameters_ex() called in the middle...)
convert_to_string_ex(bar_arg);
bar = Z_STRVAL_PP(bar_arg);
bar_len = Z_STRLEN_PP(bar_arg);
You shouldn't have to ask what happens if you leave --string-lens out. If you
have to, it's questionable whether you should be reading this document.
--with-xml[=file]
Creates the basics for phpdoc .xml file.
--full-xml
Not implemented yet. When or if there will ever be created a framework for
self-contained extensions to use phpdoc system for their documentation, this
option enables it on the created xml file.
CURRENT LIMITATIONS, BUGS AND OTHER ODDITIES
Only arguments of types int, bool, double, float, string and array are
handled. For other types you must write the code yourself. And for type
mixed, it wouldn't even be possible to write anything, because only you
know what to expect.
It can't handle correctly, and probably never will, variable list of
of arguments. (void foo(int bar [, ...])
Don't trust the generated code too much. It tries to be useful in most of
the situations you might encounter, but automatic code generation will never
beat a programmer who knows the real situation at hand. ext_skel is generally
best suited for quickly generating a wrapper for c-library functions you
might want to have available in PHP too.
This program doesn't have a --help option. It has --no-help instead.
EXAMPLE
The following _one_ line
bool my_drawtext(resource image, string text, resource font, int x, int y [, int color])
will create this function definition for you (note that there are a few
question marks to be replaced by you, and you must of course add your own
value definitions too):
/* {{{ proto bool my_drawtext(resource image, string text, resource font, int x, int y[, int color])
*/
PHP_FUNCTION(my_drawtext)
{
zval **image, **text, **font, **x, **y, **color;
int argc;
int image_id = -1;
int font_id = -1;
argc = ZEND_NUM_ARGS();
if (argc < 5 || argc > 6 || zend_get_parameters_ex(argc, &image, &text, &font, &x, &y, &color) == FAILURE) {
WRONG_PARAM_COUNT;
}
ZEND_FETCH_RESOURCE(???, ???, image, image_id, "???", ???_rsrc_id);
ZEND_FETCH_RESOURCE(???, ???, font, font_id, "???", ???_rsrc_id);
switch (argc) {
case 6:
convert_to_long_ex(color);
/* Fall-through. */
case 5:
convert_to_long_ex(y);
convert_to_long_ex(x);
/* font: fetching resources already handled. */
convert_to_string_ex(text);
/* image: fetching resources already handled. */
break;
default:
WRONG_PARAM_COUNT;
}
php_error(E_WARNING, "my_drawtext: not yet implemented");
}
/* }}} */